Buffing device



y 6, P. E. HAWKINSON 2,240,559

BUFFING DEVICE Filed Dec. 4, 1939 v g 2 Sheets-Sheet l 8/ mmmmmmm y/ May 6, I941. P. E.'HAWKINSO N 2,240,559

- BUFFING DEVICE Filed Dec. 4; 1939 2 Sheets-Sheet 2 I @pz 2 1/3294 Patented May 6, 1941-.

UNITED STATES PATENT OFFICE- .aiifiifim. I

Paul E. Hawkinson,

to Paul E. Minn.,

Minneapolis, Minn, assignor Hawkinson Company, Minneapolis, a. corporation of Minnesota Application December 4, 1939, Serial No. 307,477

, zClaims- My present invention relates to buiier devices and is particularly directed to an improved buii'er wheel or head. The improved buffer head is adapted for various diiierent kinds otwork but has been especially designed to meet the requirements of a bufier wheel for usein the bufling of tire casings in the preparation thereof for retreading.

For this particular purpose, it has been the old and common practice to use a. bufier wheel provided with permanently applied barbs or teeth. These teeth wear away quite rapidly and with this old arrangement new complete heads were frequently required.

My invention involves a repdilyreplaceable buiier strip. The coarseness and rapidity of the buffing action will depend on the nature of the barbs or cutting particles on the buffer strip and these, of course, may be varied. When the buffer strip is provided with coarse barbs or teeth, the buffing action will resemble that 01' a rasping action, but the bufier strips employed may be provided with teeth .or barbs of varying coarseness or cutting action according to the kind of work.

From the foregoing it will be understood that the term buifing" is herein used in a broad and Liberal sense.

The invention is directed particularly to the aovel features as to construction which make the ise of the inexpensive bufier strips an easy operation quickly performed.

A commercial form of the invention isillusrated in the accompanying drawings wherein the characters indicate like parts throughout he several views.

Referring to the drawings:

Fig. 1 is a perspective showing the improved hirer wheel and band applied to the rotor of n electric motor and showing also an associated rousing or shield and a transparent guard winow, which latter features constitute no part of be present invention Fig. 2 is a fragmentary section taken on the ne 2--2 of Fig. l;

Fig. 8 is a fragmentary view partly in side ele ation and partly in section showing sections of split or two-part buffer wheel and the ends of re buiier hand;

Fig. 4 is a perspective showing the buffer wheel ad band opened up and illustrating the manner applying the band thereto;

Fig. 5 is a perspective showing the opened or tread buiier wheel and band and levers for rcing the same to closed or operative positions;

a novel buffer wheel and Fig. 6 is a view in collar which constitutes an important part of the buifer wheel; 7

Fig. 7 isa view corresponding somewhat to Fig. 5 but showing the sections of the bufier wheel closed in position to receive the hub collar'which is applied thereto Fig. 8 is an end elevation showing several of the normally straight bufier strips or hands placed in nested condition for shipment or storage.

In Fig. 1 the numeral Ill indicates-an electric motor and the numeral ii the rotor shaft or spindle on which the bufier wheel, presently to be described, is detachably secured. The tillmeral i2 indicates the housing or guard associated with the wheel and in practice usually connected to the source of suction or partial vacuum. The numeral 53 indicates the transparent window or shield through which the operator observes the work being performed by the landing wheel. As before indicated, the elements i2 and it constitute no part of the present invention. w 1

The buffer wheel, in accordance with my invention, is made of two sections H and it that split the complete wheel diametrically. These sections it and it have interlapping hinge lugs i6 pivotally connected by the hinge pin it or othe "se. The said sections M and i5 at the axis of the wheel are provided with split hub sections it and i5' which, when forced together, make a complete hub. The sections it and it at one side have semi-disc-like webs that are provided with semi-cylindrical rim sections its and i 5w respectively, and at their ends they are provided with inturned flanges or lugs Nb and iEb that are tapped out to receive screws it. When the sections of the bufi'er wheel are forced together, as shown in Fig. 7. they are interlocked by a, collar ii) that can 'be freely telescoped over the same.

By reference particularly to Fig. 3 it will be noted that the band 20, at its ends, has curved portions that unite with the anchoring ends 20' and that the flanges and sem -cyl ndrical rim sections Ma and i5a are joined to their respective lugs Mb and I5!) by curved otruncated surfaces, the radii of wh ch are much greater than the radii of the curved end portions of the said band 20. This arrangement, as clearly shown in said view, Fig. 3, normally spaces the curved portions of the band from the curved portion of the ends of the segmental. sections. This is highly important for reasons above indicated, but which perspective showing a hub.

may be further explained as follows. When the segments or semi-cylindrical sections are forced together and the buffer band is tightly drawn onto the same, the curved end portions of the said band, under increasing'tension, will tend to straighten or become more nearly straight and will produce increasing resistance as the sections are closed. The arrangement should be such that the curved end portions of the band will not be brought completely into contact with the curved end portions of the segments. By such an arrangement the band will never be axially stretched and certainly not to a breaking point because the tension will always be taken up in the curved end portions of the band when the segments are closed to the limit.

The buffer band or element may take different forms but as a feature of the invention are steel strips or bands 20 that are normally straight but capable of being readily bent into circular form. The barbs on this band are preferably made by the use of a more or less dull punch or punches that produce ragged or sharp barbs or teeth 2! that have arapid cutting action. This bufllng strip has end flanges 20 that are abmptly bent inward closely approaching right angles to the bodies thereof; while the lugs Nb and lib are rounded for an important purpose which will hereinafter appear. The barbs 2| are preferably arranged in oblique cross rows to give a continuous or unbroken cutting action under rotation of the wheel.

The inturned ends or flanges 20' are perforated so that the screws 18 may be freely passed therethrough and screwed into the holes in the lugs lib, and l5b. In practice the buffer strips may vary slightly in length and in the angle in which the ends are turned inward; but in spite of this fact, it is highly important that the buil'er strip, when applied to the closed buffer wheel, will be drawn very taut but will not be broken. This is accomplished largely by the fact that after the buffer strip is applied to the wheel sections and the wheel sections are being moved together, there will be clearance between the angles at the ends of the strip and the rounded portions of the lugs Ill) and b so that in closing the wheel sections under high pressure the straightening oi the steel or metal band at its angular ends will compensate for some inaccuracies in the making of the butler strips. 0bviously when the screws 18 are inserted through the ends of the buffer strip and screwed into the lugs, the buffer strip will be very securely :anchored to the sections of the buffer wheel. Here it may be noted that the long unthreaded ends of the screws 18 assist in effecting the proper entrance of the screws and this is important especially where the alignment of the holes in the lugs and the ends of the strip is not perfect.

Obviously considerable force will be required to close the sections of the wheel with the buzflln strip or band applied thereto as shown in the drawings: and, hence, I provide levers 22 provided with pins 23 that are engageable in holes 24 in the webs of the wheel sections. When the as shown in slipped on to the shouldered or reduced end of the motor shaft or spindle II and there clamped by a nut 25, or the like, so that the wheel will be revolved with the rotor of the motor. Preferably a washer 26 is applied between the nut 25 and the hub portion of the buffer wheel so that the latter will keep the collar l9 pressed on to the hub sections. In Fig. 4 the numeral 21 shows a screwdriver used to tighten the screws la.

The fact that the bufier strips are normally straight is important for the main reason that they may be closely packed in packages oi proper shape for storage or shipment. Fig. 8 illustrates the manner of nesting the normally straight strips but in practice by giving the proper inclination to the ends 20' of the strips 20, they may be nested in complete contact.

In actual practice this improved buffer wheel structure has been found highly eflicient. Bufier strips of any desired coarseness or fineness may be produced at small cost and by the successive use thereof on the common wheel, the total cost of bufling operations has been very greatly reduced.

Another advantage in the split bufling head described, is the fact that after the collar [9 is once applied to a shaft, the device may be applied or removed radially oi the shaft, which is particularly important in that it permits the split head to be readily applied to or removed I from the intermediate portion of a shaft between other shaft carried devices without removing such other devices.

the levers are used like a pair of tongs, the wheel sections can be closed and the bumng strip tightly stretched thereon and the collar I9 then telescoped over the split or segmental hub-forming sections II and I5.

When the bufler wheel and band are applied,

A preferred commercial form of the invention has been shown in the drawings and described, but it will be understood that various alterations in the details of construction and arrangement of parts may be made within the scope of the invention herein disclosed and claimed.

What I claim is:

1. A buffer wheel made up of hingedly connected segments, each segment having an approximately semi-cylindrical rim flange terminating in radially inturned anchoring lugs, and a buffer band applied around the rim flanges of said segments and having inturned ends anchored to the respective lugs, the ends of said buffer band being joined to their inturned ends by curved portions, and said rim flanges being joined to their respective anchoring lugs by curved or truncated portionspthe radii of the arcs of which latter are much greater than the radii of the arcs of the curved ends of said buffer band, whereby, under forced closing of said segments, the curved portions of said band will be drawn into shapes more closely corresponding to the curve of the truncated portions of said rim flanges.

2. The structure defined in claim 1 in which said segments are provided with means for the detachable connection of levers thereto.

its curved end portions under straightening tension.

PAUL E. HAWKIN'SON.

Fig. '1, the entire wheel may then be 

